A STUDY ON FRAGILITY EVALUATION OF NUCLEAR POWER PLANT BUILDING BASED ON THE CONSUMED STRAIN ENERGY BY SEISMIC ANALYSIS USING 3-DIMENSIONAL NONLINEAR FEM MODEL

摘要

The evaluation based on probabilistic safety assessment (PSA) is important for nuclear power plant buildings because the risk of the occurrence of the seismic ground motions beyond the design assumption cannot be denied. For the assessment, seismic ultimate analyses of the building are necessary. In this study, seismic ultimate behavior was evaluated using the detailed 3-dimensional nonlinear FEM model. Moreover, fragility evaluation of the building is executed by using the strain energy obtained from the analysis, and the applicability of the strain energy for the fragility index was studied. In this paper, the seismic response analysis was carried out using the 3-dimensional nonlinear FEM model, and ultimate behavior was evaluated. In addition, the strain energy of each material (concrete and rebar) that the bearing wall had absorbed was evaluated. As a result, it was clarified that almost all the strain energy was absorbed by concrete. Moreover, we tried to fragility evaluation using the strain energy obtained from the results of seismic analysis. As a result, we considered that the strain energy index could be an effective option for seismic PSA estimation in the future.